Duchenne muscular dystrophy (DMD) is a lethal genetic disease that affects 1 in 3,500 boys. Accumulating evidence from multiple laboratories corroborate on the involvement of calcium misregulation and oxidative stress as key contributors to the disease, suggesting that upregulation of calcium-sequestering (CaSeq) or anti-oxidant (Antiox) pathways may serve as targets in the treament of DMD. The present application aims to identify the CaSeq/Antiox pathways most significant to the dystrophic phenotype, and assess the therapeutic potential that can be realized by a gene therapy designed to target these pathways. The project is framed by three specific aims and will utilize two murine models of DMD: the mdx and mdx:utrn-/- strains. In Aim 1, muscle cells and isolated muscle preparations will be used characterize the impact of individual CaSeq/Antiox pathways on the dystrophic phenotype. CaSeq/Antiox pathways with the most substantial impact will then be used as targets for viral-mediated gene therapies. To evaluate the efficacy of these gene therapies, dystrophic mice will be injected intravenously with recombinant adeno-associated viruses that contain CaSeq/Antiox transgenes. We will determine whether these transgenes can extend the lifespan of dystrophic mice and correct the pathophyosiology associated with dystrophin-deficiency. Although the scope of the application remains focused on DMD, we expect the therapeutic aspect of our findings to have a direct relevance in the treatment of other diseases where calcium misregulation or oxidative stress play a key role, such as Alzheimer's Disease, aging, diabetes and cardiovascular disease. In the final Aim of the application, we generate mutant mdx mice with modified CaSeq/Antiox pathways by crossing mdx mice with existing strains of mice that possess modified CaSeq/Antiox pathways. These mutant mdx mice will be valuable additions to current dystrophic mouse models, as they allow investigators to isolate the contribution of specific CaSeq/Antiox pathways to the dystrophic phenotype. PUBLIC HEALTH RELEVANCE: Duchenne muscular dystrophy is a lethal genetic disease that affects 1 in 3,500 boys. Calcium and oxygen molecules affect these diseased muscles in many ways, most of which are not well understood. This project will first study how calcium and oxygen molecules interact within muscle cells, and then subsequently examine whether controlling these molecules can be an effective way to treat this disease.